scholarly journals Effects of Estrogens and Xenoestrogens on Androgen Production by Atlantic Croaker Testes In Vitro: Evidence for a Nongenomic Action Mediated by an Estrogen Membrane Receptor1

2000 ◽  
Vol 62 (4) ◽  
pp. 995-1004 ◽  
Author(s):  
Anna Katrina Loomis ◽  
Peter Thomas
Keyword(s):  
Atlantic Croaker ◽  
Nongenomic Action

Early effects of vitamin D metabolites on phosphate fluxes in isolated rat enterocytes

1985 ◽  
Vol 248 (1) ◽  
pp. G40-G45 ◽  
Author(s):  
G. Karsenty ◽  
B. Lacour ◽  
A. Ulmann ◽  
E. Pierandrei ◽  
T. Drueke
Keyword(s):  
Vitamin D ◽  
Vitamin D3 ◽  
Vitamin D Metabolites ◽  
Dihydroxyvitamin D3 ◽  
Nongenomic Action ◽  
Efflux Rate Constant ◽  
Membrane Effects ◽  
Uptake Velocity ◽  
Vitro Effect

The present studies were designed to explore the possibility that, in addition to its well-known steroidlike action, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], the active vitamin D3 metabolite, modulates inorganic phosphate (Pi) transport across the intestinal mucosa through more rapid membrane effects. Enterocytes were mechanically isolated from the duodenojejunum of vitamin D-replete rats. In this model enterocyte Pi uptake was a temperature-dependent as well as a Na+-dependent process. In vitro addition of 1,25(OH)2D3 (1 pM) led to a significant increase in Na+-dependent initial Pi uptake velocity (iVpi) within 20 min (P less than 0.001). No effect was seen for shorter incubation times (5 and 15 min). Incubation of the cells with cycloheximide did not inhibit the hormone-mediated increase of iVpi. 25-Hydroxyvitamin D3 significantly increased iVPi (P less than 0.05) at a concentration of 1 nM but not 1 pM. Vitamin D3 at a concentration of 1 microM had no effect on iVPi. Enterocyte Pi efflux rate constant was not modified by the presence of 1,25(OH)2D3(1pM). Thus, the early in vitro effect of 1,25(OH)2D3 on Pi uptake by isolated enterocytes suggests a nongenomic action of the hormone, possibly by modifying the lipid structure of the plasma membrane.

scholarly journals Cultured Embryonic Hippocampal Neurons Deficient in Glucocorticoid (GC) Receptor: A Novel Model for Studying Nongenomic Effects of GC in the Neural System

Endocrinology ◽  
2005 ◽  
Vol 146 (9) ◽  
pp. 4036-4041 ◽  
Author(s):  
Lin Xiao ◽  
Aiqun Qi ◽  
Yizhang Chen
Keyword(s):  
Hippocampal Neurons ◽  
Neural System ◽  
Neural Cells ◽  
Rt Pcr ◽  
Nongenomic Action ◽  
The Central Nervous System ◽  
And Function ◽  
Nongenomic Effects ◽  
Novel Model

Abstract Glucocorticoid (GC) acts through both genomic and nongenomic mechanisms. It affects the structure and function of the central nervous system, especially the hippocampus. Here we report an in vitro culture system that can yield embryonic hippocampal neurons deficient in the expression of GC receptor as demonstrated by immunoblotting, immunocytochemistry, and RT-PCR. Owing to this unique feature, those neuron preparations can serve as an ideal model for studying the nongenomic actions of GC on neural cells. In this study, we found that the Erk1/2, c-Jun N-terminal kinase (JNK), and p38 MAPKs were activated in these neurons by BSA-conjugated corticosterone within 15 min of treatment. This activation was not blocked by RU38486, spironolactone, or cycloheximide. Therefore, it is concluded that the activation of MAPKs observed here was due to the nongenomic action of GC. Furthermore, a 24-h incubation with corticosterone at concentrations ranged from 10−11–10−5m did not have an effect on the viability of GC receptor-deficient neurons.

scholarly journals Pesticides Interfere with the Nongenomic Action of a Progestogen on Meiotic Maturation by Binding to its Plasma Membrane Receptor on Fish Oocytes

Endocrinology ◽  
1999 ◽  
Vol 140 (4) ◽  
pp. 1953-1956 ◽  
Author(s):  
Shampa Das ◽  
Peter Thomas
Keyword(s):  
Plasma Membrane ◽  
Receptor Site ◽  
Membrane Receptor ◽  
Spotted Seatrout ◽  
Membrane Receptors ◽  
Endocrine Function ◽  
Meiotic Maturation ◽  
Nongenomic Action ◽  
Plasma Membrane Receptor

Abstract Although many environmental contaminants disrupt endocrine function by binding to nuclear steroid receptors, it is not known whether they are capable of binding to steroid membrane receptors and interfering with nongenomic actions of steroids. The binding of several organochlorine pesticides to the plasma membrane receptor for the maturation-inducing steroid, 17,20β,21-trihydroxy-4-pregnen-3-one (20β-S), in the ovaries of spotted seatrout (Cynoscion nebulosus) was investigated in in vitro competition assays. Kepone and o,p′-DDD were competitive inhibitors of 20β-S binding and caused concentration-dependent displacement of [3H]-20β-S from its receptor site over the range of 10−4 to 10−6 or 10−7 M, whereas several other pesticides had lower affinities for the receptor. Interference with the nongenomic actions of 20β-S on final meiotic maturation of spotted seatrout oocytes (final oocyte maturation, FOM) was examined in an in vitro bioassay. A concentration-dependent inhibition of FOM in response to 20β-S was observed after 5 min and 12 h exposure to the same range of Kepone and o,p′-DDD concentrations (10−4 to 10−6 or 10−7 M). The close correspondence between competitive binding of the two pesticides to the 20β-S membrane receptor and their inhibition of 20β-S induced FOM suggests a mechanism of endocrine disruption mediated by binding to a steroid membrane receptor and antagonism of a nongenomic steroid action.

scholarly journals Regulation of β-Catenin by a Novel Nongenomic Action of Thyroid Hormone β Receptor

2008 ◽  
Vol 28 (14) ◽  
pp. 4598-4608 ◽  
Author(s):  
Celine J. Guigon ◽  
Li Zhao ◽  
Changxue Lu ◽  
Mark C. Willingham ◽  
Sheue-yann Cheng
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormone Receptor ◽  
Critical Role ◽  
Human Thyroid ◽  
Binding Studies ◽  
Nongenomic Action ◽  
Oncogenic Protein ◽  
In Cells

ABSTRACT We previously created a knock-in mutant mouse harboring a dominantly negative mutant thyroid hormone receptor β (TRβPV/PV mouse) that spontaneously develops a follicular thyroid carcinoma similar to human thyroid cancer. We found that β-catenin, which plays a critical role in oncogenesis, was highly elevated in thyroid tumors of TRβPV/PV mice. We sought to understand the molecular basis underlying aberrant accumulation of β-catenin by mutations of TRβ in vivo. Cell-based studies showed that thyroid hormone (T3) induced the degradation of β-catenin in cells expressing TRβ via proteasomal pathways. In contrast, no T3-induced degradation occurred in cells expressing the mutant receptor (TRβPV). In vitro binding studies and cell-based analyses revealed that β-catenin physically associated with unliganded TRβ or TRβPV. However, in the presence of T3, β-catenin was dissociated from TRβ-β-catenin complexes but not from TRβPV-β-catenin complexes. β-Catenin signaling was repressed by T3 in TRβ-expressing cells through decreasing β-catenin-mediated transcription activity and target gene expression, whereas sustained β-catenin signaling was observed in TRβPV-expressing cells. The stabilization of β-catenin, via association with a mutated TRβ, represents a novel activating mechanism of the oncogenic protein β-catenin that could contribute to thyroid carcinogenesis in TRβPV/PV mice.

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